Assessment of occupational exposures is a crucial factor in evaluating dose-response relationships and most studies conducted by the Branch have an extensive exposure assessment component. Major assessment efforts in cohort studies have involved exposures to asbestos, organic solvents, pesticides, benzene, xylene, toluene, and diesel fumes. In the case- control design, jobs have been evaluated for a wide variety of exposures, including chlorinated hydrocarbons and other solvents, asbestos, formaldehyde, electromagnetic fields, physical activity, nitrosamines, polycyclic aromatic hydrocarbons and pesticides. These exposures have been evaluated in studies of cancer of the peritoneum, breast, kidney, stomach, nasopharynx, esophagus, pancreas, brain, and lymphatic and hematopoietic system and for studies of parental occupation and childhood cancers. Methodologic studies are also conducted to improve exposure assessment techniques and to understand exposure patterns. Thirty job-specific questionnaires have been developed for a new case-control study of nonHodgkins lymphoma that allow collection of detailed solvent information. Comparison of jobs identified on death certificates is being made with work history records. Investigations are being made on the reliability of industrial hygienists assessing exposures and viewing a videotape of pesticide applications. A computer program to assist in exposure assessment for cohort and for case-control studies is being developed. A review of pesticide information available in the public arena provided guidance on how to assess exposures to migrant workers. A report describing the exposure assessment procedures in the Chinese benzene study was developed. A review paper indicated what types of data are needed for epidemiologic studies and how they can be used. Areas of future challenges in the field of exposure assesment were described. - occupation, exposure assessment, asbestos, solvents, pesticides, benzene, xylene, toluene, diesel , formaldehyde, physical activity, nitrosamines, polycyclic aromatic hydrocarbons, peritoneal cancer, breast cancer, kidney cancer, stomach cancer, nasopharyngeal cancer, esop - Human Subjects & Human Subjects: Interview, Questionaires, or Surveys Only